Fabrication of a carbon nanotube-based gas sensor using dielectrophoresis and its application for ammonia detection by impedance spectroscopy

Junya Suehiro, Guangbin Zhou, Masanori Hara

Research output: Contribution to journalArticle

212 Citations (Scopus)

Abstract

This paper describes a new method for fabricating a gas sensor composed of multi-wall carbon nanotubes (MWCNTs) using dielectrophoresis (DEP). MWCNTs dispersed in ethanol were trapped and enriched in an interdigitated microelectrode gap under the action of a positive DEP force that drove the MWCNTs to a higher electric field region. During the trapping of MWCNTs, the electrode impedance varied as the number of MWCNTs bridging the electrode gap increased. After the DEP process, the ethanol was evaporated and the microelectrode retaining the MWCNTs was exposed to ammonia (NH3) gas while the electrode impedance was monitored. It was found that the electrode impedance was altered by ppm-levels of ammonia at room temperature. The ammonia exposure decreased the sensor conductance, while the capacitance increased. The sensor showed a reversible response with a time constant of a few minutes. The conductance change was proportional to ammonia concentration below 10 ppm and then gradually saturated at higher concentrations. Effects of the number of trapped MWCNTs on sensor response were also discussed.

Original languageEnglish
JournalJournal of Physics D: Applied Physics
Volume36
Issue number21
DOIs
Publication statusPublished - Nov 7 2003

Fingerprint

Carbon Nanotubes
Electrophoresis
Chemical sensors
Ammonia
ammonia
Carbon nanotubes
carbon nanotubes
Spectroscopy
impedance
Fabrication
fabrication
sensors
gases
spectroscopy
Electrodes
electrodes
Microelectrodes
Sensors
Ethanol
ethyl alcohol

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

Cite this

@article{f8febc5f562a4701aea1452c143f1a43,
title = "Fabrication of a carbon nanotube-based gas sensor using dielectrophoresis and its application for ammonia detection by impedance spectroscopy",
abstract = "This paper describes a new method for fabricating a gas sensor composed of multi-wall carbon nanotubes (MWCNTs) using dielectrophoresis (DEP). MWCNTs dispersed in ethanol were trapped and enriched in an interdigitated microelectrode gap under the action of a positive DEP force that drove the MWCNTs to a higher electric field region. During the trapping of MWCNTs, the electrode impedance varied as the number of MWCNTs bridging the electrode gap increased. After the DEP process, the ethanol was evaporated and the microelectrode retaining the MWCNTs was exposed to ammonia (NH3) gas while the electrode impedance was monitored. It was found that the electrode impedance was altered by ppm-levels of ammonia at room temperature. The ammonia exposure decreased the sensor conductance, while the capacitance increased. The sensor showed a reversible response with a time constant of a few minutes. The conductance change was proportional to ammonia concentration below 10 ppm and then gradually saturated at higher concentrations. Effects of the number of trapped MWCNTs on sensor response were also discussed.",
author = "Junya Suehiro and Guangbin Zhou and Masanori Hara",
year = "2003",
month = "11",
day = "7",
doi = "10.1088/0022-3727/36/21/L01",
language = "English",
volume = "36",
journal = "Journal Physics D: Applied Physics",
issn = "0022-3727",
publisher = "IOP Publishing Ltd.",
number = "21",

}

TY - JOUR

T1 - Fabrication of a carbon nanotube-based gas sensor using dielectrophoresis and its application for ammonia detection by impedance spectroscopy

AU - Suehiro, Junya

AU - Zhou, Guangbin

AU - Hara, Masanori

PY - 2003/11/7

Y1 - 2003/11/7

N2 - This paper describes a new method for fabricating a gas sensor composed of multi-wall carbon nanotubes (MWCNTs) using dielectrophoresis (DEP). MWCNTs dispersed in ethanol were trapped and enriched in an interdigitated microelectrode gap under the action of a positive DEP force that drove the MWCNTs to a higher electric field region. During the trapping of MWCNTs, the electrode impedance varied as the number of MWCNTs bridging the electrode gap increased. After the DEP process, the ethanol was evaporated and the microelectrode retaining the MWCNTs was exposed to ammonia (NH3) gas while the electrode impedance was monitored. It was found that the electrode impedance was altered by ppm-levels of ammonia at room temperature. The ammonia exposure decreased the sensor conductance, while the capacitance increased. The sensor showed a reversible response with a time constant of a few minutes. The conductance change was proportional to ammonia concentration below 10 ppm and then gradually saturated at higher concentrations. Effects of the number of trapped MWCNTs on sensor response were also discussed.

AB - This paper describes a new method for fabricating a gas sensor composed of multi-wall carbon nanotubes (MWCNTs) using dielectrophoresis (DEP). MWCNTs dispersed in ethanol were trapped and enriched in an interdigitated microelectrode gap under the action of a positive DEP force that drove the MWCNTs to a higher electric field region. During the trapping of MWCNTs, the electrode impedance varied as the number of MWCNTs bridging the electrode gap increased. After the DEP process, the ethanol was evaporated and the microelectrode retaining the MWCNTs was exposed to ammonia (NH3) gas while the electrode impedance was monitored. It was found that the electrode impedance was altered by ppm-levels of ammonia at room temperature. The ammonia exposure decreased the sensor conductance, while the capacitance increased. The sensor showed a reversible response with a time constant of a few minutes. The conductance change was proportional to ammonia concentration below 10 ppm and then gradually saturated at higher concentrations. Effects of the number of trapped MWCNTs on sensor response were also discussed.

UR - http://www.scopus.com/inward/record.url?scp=0242573687&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0242573687&partnerID=8YFLogxK

U2 - 10.1088/0022-3727/36/21/L01

DO - 10.1088/0022-3727/36/21/L01

M3 - Article

VL - 36

JO - Journal Physics D: Applied Physics

JF - Journal Physics D: Applied Physics

SN - 0022-3727

IS - 21

ER -